Could someone please help me calculate the t-score for this question?

Question

135 participants with the mean score being 23.1 and the standard deviation is 4.1 (minimum score 13, maximum 35). My score was 19. what was my t-score?

Also, help with the z-score? Was the z-score z= -1 ?

Answer 1

no idea

Answer 2

I've done this before but don't remember the formulas...

Will see if I can look it up.

t = [ x - μ ] / [ s / sqrt( n ) ]

x is the sample mean, μ is the population mean, s is the standard deviation of the sample, n is the sample size, and t is the t score.

t = [ 19 - 23.1 ] / [ 4.1 / sqrt( 135 ) ]

t = (-4.1) / (4.1/11.62)

t = (-4.1)/(0.35)

t = -11.71

Not sure if that's right. eek. I have'nt done this in a while...

If that doesn't look right have a look at http://stattrek.com/Tables/t.aspx

As for the z-score :

z = (X - μ) / σ

X is a normal random variable, μ is the mean, and σ is the standard deviation.

I also got -1 for the z-score.

Good luck.